Experimental investigation of still performance for different active solar still designs under closed cycle mode

This paper presents a study into the enhancement of the productivity attained by a proper modification in the system designs. The basic heat and mass transfer expressions for designing solar stills were derived in terms of design and climatic parameters. These solar stills were based on using a direct solar energy collection unit integrated with flash evaporation, distillation equipment and air transportation. The main objective of this study is to estimate the water production and still efficiency for different types of active solar stills in certain locations. In this investigation, proper modifications in the system designs were also made and compared on daily yields and daily still efficiencies. It was observed that a maximum daily yield of 12.37 I was obtained from the circular box solar still unit in Kayseri, Turkey. This study shows that the design of the circular box active solar still also provides the highest overall daily still efficiency, which is about 68.1%, in that of the active solar stills. It is clear that there is a significant effect on daily yield due to the proper modifications in the system designs. (C) 2012 Elsevier B.V. All rights reserved.